How to model this Pattern
You can model only one segment of a pattern then repeat it on x and y axis with array modifiers.

If you need a repeating pattern on complex object try tissue plugin 

http://www.co-de-it.com/wordpress/code/blender-tissue

Here is fast preview of the workflow, you just create some planes make some loop cuts move edges up and down



add array modifiers to see the pattern, add more planes, then increase array count and add solidify modifier, you can always adjust or modify your main object later...